1. Field of the Invention
The present invention relates to a polycarbonate polyurethane resin composition. The present invention specifically relates to a water-dispersable polycarbonate polyurethane resin composition which gives excellent oil resistance, solvent resistance, water resistance and abrasion resistance when used to treat various types of fibers, and which has a soft and resilient hand quality.
2. Description of the Related Art
Conventional processes for producing aqueous polycarbonate polyurethane resins are the same as those for producing general aqueous polyurethane resins, i.e., one or more anionic, cationic or nonionic hydrophilic groups are introduced into the polyurethane resin skeleton to render it water-soluble, or a large amount of an emulsifying agent is mixed with the hydrophobic polyurethane resin and emulsified dispersion is forcibly achieved by mechanical shear. Almost all polyisocyanates are used alone.
Water-dispersable polyurethane resins used as polymer treatment agents for aqueous solvents are characterized by a low degree of pollution, high safety and ease of handling, and using polycarbonate polyols can provide excellent physical properties including light fastness, heat resistance, hydrolysis resistance and oil resistance, to allow application in a wider range of fields.
However, while polyurethane resins obtained using polycarbonate polyols as the main polyol components give tough film strength and excellent physical properties such as light fastness, heat resistance, hydrolysis resistance and oil resistance, when they are used for padding, immersion or coating treatment of various fiber materials the hand quality of the treated fabrics tend to be very hard, thus reducing their suitability for practical use.
In contrast, self-emulsifying resins obtained by introducing hydrophilic groups into the polyurethane skeletons of the above-mentioned water-dispersable polyurethane resins can give aqueous dispersions of high molecular weight and with a highly crosslinked structure, but despite considerable efforts at improvement, the influence of the introduced hydrophilic groups has not always given satisfactory results, especially in terms of hot water resistance and long-term moist heat resistance.
Also, in the case of the hydrophobic polyurethane resins mixed with large amounts of emulsifying agents and subjected to mechanical shear for forced emulsified dispersion, the effect of the presence of the emulsifying agents in large amounts inhibits the coatability, and thus at the present time, their physical properties are unsatisfactory. Incidentally, when the amount of emulsifying agent is reduced to resolve the problem, the stability of the dispersion itself is notably impaired.